1. Field of the Invention
The invention relates to optical transceivers, and in particular to multi-laser transmitter assemblies or modules that provide an communications interface between a computer or communications unit having an electrical output connector or interface and an optical fiber, such as used in high speed fiber optic communications links such as wide wavelength division multiplexed (WWDM) networks.
2. Description of the Related Art
A variety of optical transceivers are known in the art which include an optical transmit portion that converts an electrical signal into a modulated light beam that is coupled to an optical fiber, and a receive portion that receives an optical signal from an optical fiber and converts it into an electrical signal. Traditionally, optical transmitter sections include one or more semiconductor lasers and an optical assembly to focus or direct the light from the lasers into an optical fiber, which in turn, is connected to a receptacle or connector on the transceiver to allow an external optical fiber to be connected thereto. The semiconductor lasers are typically packaged in a hermetically sealed can or similar housing in order to protect the laser from humidity and other harsh environmental conditions. The semiconductor laser chip is typically a few hundred microns to a couple of millimeters wide and 100-500 microns thick. The package in which they are mounted typically includes a heat sink or spreader, and has several electrical leads coming out of the package to provide power and signal inputs to the laser chips. These electrical leads are then soldered to the circuit board in the optical transceiver.
In high speed systems requiring the use of several lasers, the hermetic packages take considerable space, and it is desirable to provide a more compact arrangement.